I had a one of my marathon runners write to me this week asking the following question:

“Yesterday after running I had stomach cramps and digestive problems all day and evening. I have overheard people talking a couple of times about how if they drink one of the “Power” drinks or eat one of the “Gu” type products, this happens. Is it just me or is this a common occurrence. Any suggestions?

During my run this weekend, I had Glukose at all but one aid station and ate two of the Power Bar Gel packets and one Gu packet. I ate a banana in my truck on the way home. Before I ran I ate a power bar and drank a bottle of water.”

Here’s my answer to this important question in hopes that it may help out on your long runs this weekend.

First, it’s not uncommon to have stomach problems after taking in these sugary training foods in addition to the stress of a really long run. It’s important when managing our food intake that we do a couple of important things: one being to ensure that we dilute any of the gel products coming into the stomach and the other being to vary the foods that we’re eating as the distance become very long. It is also important to eat before and after runs to set the foundation for the workout and then help recover.

Here are some suggestions that may help with keeping your digestive system smoothed out during and after your long runs:1) Eat something solid well ahead of your run. I usually try to eat a bagel with peanut butter and jelly and a banana when I get up in the morning – usually 1 to 1 1/2 hours or so before running. I may also sneak in another snack within the last 30 minutes before the run – such as half of a PowerBar.

2) Drink plenty of water when eating gel packs. The concentration of the sugars in gel packs is high enough to cause stomach upset on its own. You need to drink plain water with these products to lower the concentration of sugar in your stomach. One of the pitfalls here is that runners often drink an energy drink with their gel – and this just adds more sugar to the mix. Here is my strategy: I drink my Gleukos energy drink at one aid station and then take my gel with plain water at the next. I alternate in order to avoid mixing the two.

3) If you’re getting sick, try not to use more than one type of gel pack until you figure out if one brand may be making you sick. Each of the gel products has a different mix of ingredients and these all have different impacts on peoples’ stomachs. Keep trying until you find something that works for you.

4) Mix in some salty or more solid foods during the run itself. Many times when people have stomach problems, if they add potato chips, pretzels or fruit to the mix, it will help calm the stomach. Personally I love a peanut butter and jelly sandwich mid-race/workout to settle the stomach down. When I’m training for very long events (Ironmans or Ultras), I commonly eat “real” food during my workouts, such as a half of a turkey sandwich every few hours to keep from developing the “gut rot” of eating too much sugar at a time.

5) Eat some solid food and drink plenty of water after the run. Try to get in something solid within the first 30-45 minutes after the run – like a sandwich. Aim to get in 15G of protein after a long run to help with recovery and calm the stomach. If you’re having stomach issues, I’d probably avoid using a recovery drink and eat a sandwich and some fruit instead.

These are some things to try. The most important thing is this: don’t stop eating/drinking during the runs for fear of an upset stomach. You need the fuel as energy. Experiment with what works to make sure that you get the fuel that you need without the stomach upset.

Post-script: the runner wrote me back after trying some of these suggestions and found that by switching to a single-brand of gel he was able to get rid of most of the stomach upset this past week. See it works! Coach Joe

Thankyou very much, I have always had this problem after a big run and my mom keeps saying that i am not having enough stamina, i will try it and i am sure its going to be great. Thankyou, thankyou very much,

I have experienced similar problems but I don't drink gatorade or any of those gu products after a bad experience several years ago during a marathon! Can the shot blocks cause the same problem? I only eat those combined with Nunn tablets in water. During a 20 mile run, I'll consume about 4 of them.
Thanks,
Laurie

It looks to me like you’re doing the right things, but let me make two suggestions for you:

1) Nuun is great and you can drink a lot of it without risking hyponatremia (fluid overload), so in trying to stomp this out try a workout where you increase the amount of fluid (Nuun, not water) by a considerable amount. So, for example, if you’re drinking 2 bottles during your run, drink 4. And pre-hydrate well, by drinking a whole bottle the night before and a bottle two hours before your run. If this helps, then the problem was not getting in enough fluids and electrolytes (often the case).

2) It could be that one of the particular ingredients in your blocks (or food) are causing the problem. I’d trying switching to another brand for a workout, but otherwise keeping things constant. Make sure that if you try another food that the food contains another type of sugar (look for things like maltodextrin, fructose, sucrose, or dextrose on the label. The fewer different sugars the better for trouble-shooting purposes. You may want to try something like Honey Stinger that is made from honey, which is quite easy to digest.

Remember to only tweak one thing each workout until you find the source of the problem. This will allow you to then no for certain that you’ve found the root cause of the problem.